10d+5n=220
divide both sides by 5
2d+n=44
d=13+n
sub 13+n for d in other equatin
2(13+n)+n=44
26+2n+n=44
26+3n=44
minus 26 both sides
3n=18
divide both sides by 3
n=6
sub back
d=13+n
d=13+6
d=19
19 dimes
6 nickles
The correct answer is Choice B: 720.
To solve this, you have to use the Fundamental Counting Principal. You find the total number of options for each of the digits, then multiply them together.
For the first one, there are 10 options, then 9 options and finally 8 options.
10 x 9 x 8 = 720
He will bike 920 km because 4 days time 4 equals 16 days and 230 km times 4 equals 920 km.
plz give mw brainliest if this helped
Answer:
Step-by-step explanation:
Algebra level